Centralized radio system



A. R. HOPKINS cEtiTRALIZED RADIO SYSTEM Fiied Au 15,;1935 J OFF-20 IINVENTOR' A.R.HOP NS A'fTORNEY Patented Sept. 14, 1937 UNITED STATES 2,092,879 I CENTRALIZED RADIO SYSTEM Alva R. Hopkins, Merchantville, N. Jl, assignor to Radio Corporation of America, a corporation 7 of Delaware Application August 13, 1935, Serial No. 35,903

3 Claims.

An object of this invention is to provide a centralized radio system for the economical distribution of radio programs through several rooms in a dwelling, hotel, school or other building and 5 in which a station selector unit is located in each room by means of which any desired station may be received and caused to operate the loudspeaker located in the room.

A further object is to provide an additional control station located at some central point in the building and which is so connected to the several loudspeakers and the different program channels that the operator thereof may silence the loudspeaker in any room or connect it to any 7 program channel he prefers.

A still further object of the invention is to provide an audio sound source such as a microphone or phonograph pickup device at the central control station which may be connected to the audio frequency amplifier of one of the station receivers so that the operator may make an-' nouncementsto any desired room or number of rooms. Other objects of the invention will become apparent to those skilled in the art as the description thereof proceeds. For a better understanding of the invention, however, reference is made to the accompanying drawing in which the single figure shows diagrammatically a centralized radio system arranged according to my invention.

In the drawing each of the channel racks l0 and H comprises a tunable radio receivenaudio frequency amplifier and loudspeaker, a more detailed description of these units being given in the patent to A. F. Van Dyck, 1,968,546 granted July 31, 1934. These units are preferably located at a central location such as in the principals ofiice of a school. It will also be understood that the radio receiver of each unit is preferably tuned 0 to receive a different broadcasting station so that the channel A carries the modulation frequency of station A and channel B that of a station B. Located in a room remote from the channel racks such as in a classroom designated by the dotted lines R is a channel selector device [2 comprising a switch blade I3 contacts I, 2 and a third contact marked Off. nected to channel A and contact 2 to B while switch [3 is connected to a terminal R. C. of .a master control panel M to be described. It will also be understood that the selector device l2 may include a volume control unit as described in the Van Dyck patent above noted. A sound repro- 56 ducer such as a loud speaker L5 is preferably also As shown contact I is conmounted in the room R and connected as shown to amovable switch blade [6 of the unit l4.

Located in another room as designated by line B. are a selector device I2 and speaker connected and arranged similarly to those in room R. Located at the central location preferably near 5 the channel racks l0, II is the master control panel I 4 which is provided with a number of similar switch control units S. Each unit is provided with a movable switch blade 16, a contact marked Off and also a contact for each channel of the system, the contacts I. being connected to channel A and contacts 2 to channel B. It will be understood that a control unit S will usually be provided for each speaker to be controlled and as many switch positions on each as there are radio channels provided.

In the operation of the system the principal will usually leave the switches IE on contacts R. C. as shown. The instructor may then throw his speaker l5 out of circuit by placing switch l3 in the position shown orhe may connectit to channel A by moving it to position I or to channel B by moving it to position 2. It will be seen that with the switch in position I the principal 25 may silence the corresponding speaker by moving the corresponding switch Hi to the off contact or he may connect it to channel B by moving switch IE to position 2. It will thus be seen that the several speakers are under the control of the 30 principal or other central station supervisor at all times irrespective of the position to which the switches l3 may be adjusted and he may'connect all speakers to the same or to different chan-' nels according to his desire. While the return 5 lines fromthe speakers to the low potential side of the audio output terminals l8 are shown as ground, it will be understood that two wire connections may be used instead Input jack terminals IQ of the audio frequency 40 amplifier of one or more 'of the channels may be connected when the station is detuned to the output terminals of a microphone 2B or a phonograph pickup and then by connecting one or more speakers to the corresponding channel, the principal may address the occupants of one or more rooms by suitably setting one or more of the switches It. Or if a phonograph pickup is used instead, recorded music may be reproduced in 50 any desired room or rooms as desired.

While only two speakers and control units l2 have been shown, it will be understood that any desired number'may be used within the available power output of the audio amplifiers of the, re-" 55 ceivers, the number of switch units S being made to correspond.

Having described my invention what I claim as novel and desire to secure by Letters Patent is:

1. In a centralized radio system, the combination of a plurality of audio frequency current sources, a plurality of sound reproducers located at points remote from said sources, connections between said reproducers and sources-at least one of said connections including a switching device located adjacent said reproducer and arranged to connect it to either of said sources and a second switching device located at apoint remote from said reproducer and arranged to connect it to either of said sources irrespective of the position of said first named switching device and a line connectingsaid switching devices in series.

2-. In a centralized radio system, the combination of a panel comprising a radio receiver having audio frequency output terminals, means for selectively connecting a microphone to said terminals, a sound reproducer located at a point remote y from said receiver, a switch arranged to connect said reproducer to said output terminals and a second switch located adjacent said microphone arranged to connect said microphone and output terminals to said speaker irrespective of whether the first named switch is open or closed and a line connecting said switches in series.

3. In a centralized radio system, the combination of a radio receiver having output terminals, an amplifier panel having output terminals one of each' of said pairs of output terminals being grounded, a microphone connected to said amplifier panel, a first and a second loud speaker located at points remote from said panels-one terminal of each of said speakers being grounded, a switching device arranged to connect both said speakers to said receiver output terminals, and a second switching device located adjacent said microphone arranged to disconnect said first speaker from said receiver output terminalsand connect it to the output terminals of said amplifier. I

ALVA R. HOPKINS. 

